Car washes typically provide rotatable wheel brushes which are disposed along the wash path and are spring urged inwardly for brushing engagement with the vehicle wheels as the latter moves through the washing apparatus. The tire brush is typically of small diameter but of substantial axial length, and is oriented for rotation about a generally horizontal axis so as to engage the exposed side of the vehicle tire to effect cleaning thereof. While cleaning of tires, particularly white sidewall tires, has long been a serious problem, nevertheless this problem is becoming more complex for car wash operators in view of changes both in automotive design and in control of pollutants generated during the washing operation. While it has been conventional to utilize rather strong chemicals in conjunction with the tire brush in order to clean and whiten the sidewalls of vehicle tires, nevertheless such chemicals can cause damage to the car parts and also undesirably pollute the sewage system. The use of such chemicals is being eliminated or minimized.
To effectively clean white sidewalls, particularly in the absence of cleaning chemicals, tire brushes have been constructed utilizing bristles made of silicon carbide-impregnated nylon filaments (a typical material being manufactured by E. I. DuPont and sold under the trademark TYNEX "A"). Anything less abrasive than this silicon carbide-impregnated filament has been found to be ineffective for cleaning white sidewalls, and tire brushes employing abrasive bristles of this type are now rather universally utilized.
However, more vehicles are now being manufactured employing aluminum rims and/or hubcaps, which rims and caps typically have a soft protective coating provided thereon. The current tire brushes employing silicon carbide-impregnated bristles, however, are sufficiently aggressive that if they rub against the coated aluminum surfaces, the bristles can cause damage by effecting removal of the coating and scratching of the underlying aluminum surface. This scratching and damage is caused when the tire penetrates too far into the brush allowing the aggressive and abrasive material of the bristles to touch the aluminum wheel parts. However, several factors tend to cause too much penetration:
(a) the operator may be using too much pressure (either spring or hydraulic pressure) to push the brush against the side of the tire; PA1 (b) the width of cars can vary significantly, and hence the wider cars themselves tend to result in greater pressure between the brush and tire due to the manner in which the support for the brush automatically urges the brush inwardly for engagement with the tire; PA1 (c) the use of balloon tires on vehicles increases the brush penetration and pressure; and PA1 (d) the wheel washing unit stops may not be adjusted to allow the brush to move far enough away from the path of vehicle travel, particularly for wider cars.
As is apparent from the above, not all of the parameters which control wheel pressure can be controlled by the operator of the washing apparatus. However, even when all of the above factors have been adjusted or remedied to the maximum extent possible by the operator, there is still a danger of causing damage to the aluminum parts since the above parameters obviously require extremely close control and constant adjustment in order to finely balance the optimum conditions required to permit proper cleaning of the white sidewall tires without damaging the aluminum wheel parts.
The problem of cleaning the white sidewalls associated with vehicle wheels employing aluminum parts, however, is made even more difficult by tire design changes. Vehicle and tire manufacturers have modified the tire designs such that the white sidewalls have been lowered closer to the floor, and the gap between the white sidewall and the aluminum wheel (or rim) has been reduced. The net result is that the rim itself is positioned closer to the floor or surface on which the tire rolls. There is less available space for engaging and cleaning the sidewall of the tire at the lowermost portion thereof. On the other hand, the car wash apparatus normally employs a roller which travels along near the floor and engages directly behind the vehicle tire so as to push the vehicle along the washing path. The presence of this roller necessitates that the tire brush itself be positioned at least a few inches upwardly above the floor so as to provide clearance for the pushing roller, and this coupled with the tendency for the wheel rims to be positioned lower relative to the floor, makes it virtually impossible for the tire brush to contact and clean the sidewalls of the tire without also making rather significant contact with the aluminum wheel parts.
Accordingly, the present invention relates to a tire brush designed for use in a car wash apparatus, which tire brush is believed to represent a significant improvement in that it is capable of providing satisfactory cleaning of white sidewall tires while minimizing the potential of damage to aluminum wheel parts.
In the improved tire brush of this invention, the brush includes a large plurality of radially projecting bristles which define an axially elongated cylindrical array. This cylindrical array of bristles is itself defined by a first cylindrical array formed by stiff abrasive bristles, such as silicon carbide-impregnated nylon bristles. This first cylindrical array of abrasive bristles is of a first diameter. The overall cylindrical bristle array includes a second cylindrical array of bristles having a second diameter which is greater than said first diameter, this different in diameter typically being in the range of from one to two inches. The bristles of the second cylindrical array are, in relationship to the abrasive bristles of the first cylindrical array, of low abrasiveness and hence are hereinafter referred to as the nonabrasive bristles. These nonabrasive bristles are typically of a plastic material, such a polypropylene or nylon, and are free of abrasives. The bristles of this second cylindrical array are stiff so as to control the penetration of the brush against the wheel, whereby they will permit sufficient penetration so that the abrasive bristles of the first cylindrrcal array can clean the white sidewalls, while at the same time these abrasive bristles will not make any significant contact with the aluminum parts so that the latter are cleaned by the tips of the nonabrasive bristles defining the second cylindrical array. The bristles defining the first and second cylindrical array are generally uniformly dispersed circumferentially and axially of the brush to provide for optimum and uniform cleaning.
In the improved tire brush of the present invention, the free outer end portions of the nonabrasive bristles are preferably split or "flagged", whereby the free end portion of each nonabrasive bristle defines a large number of very small fiberlike end parts which are relatively soft. These flagged ends provide a soft and fluffy outer layer around the brush which is not only highly effective for cleaning the wheel and specifically the aluminum wheel parts, but this outer fluffy layer is also highly effective for retaining the milder cleaning solution that is used in conjunction with the tire brush, thereby further improving the effectiveness of the cleaning action. The flagged ends of the nonabrasive bristles extend inwardly of the bristle through a length which is less than the difference in the radial lengths of the abrasive and nonabrasive bristles, whereby the nonflagged portions of the nonabrasive bristles project radially outwardly and define a diameter which is slightly greater than the diameter of the abrasive bristles to hence control penetration of the tire into the brush. Further, the flagged ends of the nonabrasive bristles will continue to flag as the brush is worn and the overall brush diameter becomes smaller, so that the effectiveness of the softer flagged ends will continue as the brush is being used. However, because the bristles defining the second diameter are nonabrasive, they have less tendency to wear than the abrasive bristles, and hence the second diameter will continue to remain larger than the first diameter even as the brush undergoes wear.
Other objects and purposes of the invention will be apparent to persons familiar with brushes of this general type upon reading the following specification and inspecting the accompanying drawings.